Office



(No Model.)

2'SheetsSheet 1, W. W. HOLMES. SLACK ADJUSTER FOR BRAKES.

- Patented Feb. 23, 1897'.

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SLACK ADJUSTER FOR BRAKES.

No. 577,659. Patented Feb. 23, 1897.

74. f" l l M ///////////AIIIBf//////////////// fi F m i m w WITNESSES: I y Q R 7 ATTORNEY.

rrhn STATES arnnr rrron.

WILLIAM W. HOLMES, OF CHICAGO, ILLINOIS, ASSIGNOR TO CHARLES F. QUINCY, OF SAME PLACE.

SPECIFICATION forming part of Letters Patent hie. 577,659, dated February 23, 1897'.

Application filed December 23, 1896. Serial No. 616,746. (No model.)

To ctZZ whom it nttty concern.-

Be it known that 1, WILLIAM W. HOLMES, a citizen of the United States, residing at Ohicago, in the county of Cook, State of Illinois, have invented certain new and useful Improvements in Slack-Adjusters for Brakes; and I hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, in which A Figure 1 is a top plan view of an air-brake cylinder having combined therewith slackadjuster mechanism embodying my invention, the take-up-motor cylinder being partly broken away to show the piston and its spring. Fig. 2 is a longitudinal vertical sectional View of the air-brake cylinder, showing those portions of the slack-adjuster mechanism located within said cylinder, the screw, ratchet-nut, stirrup or fulcrumguide, and take-up motor being shown in elevation. Fig. 3 is an end view, in elevation, of the air-brake cylinder, showing the relation of the slackadjuster mechanism to the cylinder-head. Fig. A is a detail sectional view of a portion of the air-brake cylinder and its head, showing the cored port leading to the take-up motor of the adjuster mechanism; and Fig. 5 is an elevation of a portion of the head of the air-brake cylinder, showing the opening of the cored port of the air-brake cylinder.

Like symbols refer to like parts Wherever they occur.

My invention relates to certain improvements in slack-adjusters for brakes, and is more especially directed to that class of slackadjusters wherein are combined, with the cylinder-levers ofa brake system, a movable fulcrum-block and screw-and-ratchet mech-- anism for shifting the movable fulcrum to compensate for the Wear of the brake-shoes and other slack incident to the brake-rigging.

struction or its equivalent embodies the main I feature of my invention.

There are other minor features of invention, all as will hereinafter more fully appear.

I will now proceed to describe my invention more fully, so that others skilled in the art to which it appertains may apply the same.

In the drawings, A indicates the air-brake cylinder, B O the cylinder-levers, and D the tie-rod, of the usual or any approved form of an air-brake system.

The lever B is, as usual, pivotally connected to the end of the piston-rod P, while the lever C is pivoted on a movable fulcrum-block F, which travels in a stirrup or fulcrum-guide G, attached to or supported from the cylinder-head a.

The movable fulcrum-block F is caused to 4 travel along the stirrup or guide G by means of a screw-rod S, attached thereto, and which enters the air-brake cylinder A through an opening in the cylinder-head a, which screwrod carries a ratchet-nut R, having its bearing on the cylinder-head a, and which is ro- A, at a point just beyond the predetermined or normal travel of the piston-head H, is a cored port p, having its outlet through the head a where it receives the pipe m leading to the take-up motor M.

M indicates the take-up motor, mounted or supported on the stirrup or fulcrum-guide G in juxtaposition to head a of brake-cylinder A. Said motor may be of any desired form, but for the present purposes it has been shown (see Fig. 1) as one having the return stroke of its piston effected by a spring and its piston-rod M connected by an arm M with a rod 1", arranged in the plane of ratchet-nut R parallel with the piston-rod M and carrying a gravity-pawl 0", which is arranged to actuate the ratchet-nut R on the return stroke of the motor-piston.

The construction being substantially such as hereinbefore set forth, its operation will be as follows: So long as there is no material slack in the brake system or wear of the brakeshoes the piston-head H will have but its normal travel or stroke and the slack-adjuster mechanism will remain quiescent, but so soon as the wear on the brake-shoes (or slack in the system) is sufficient to cause the pistonhead H to exceed its normal stroke the port 1 Will be uncovered and air from the brakecylinderA will pass therethrough and by pipe m to the cylinder of the take-up motor M, acting on its piston, and through rod 1" cause the idle travel of pawl 1" over ratchet-nut R. Immediately the pressure in air-brake cylinder A is reduced (brakes taken off) the return stroke of piston-head H will unclose port 19 to the front (or exhaust side) of the piston-head, and take-up motor will then exhaust through pipe m, port 19, and the piston-rod opening of air-brake cylinder A. At the same time the spring of the take-up-motor piston will cause the return stroke (or working stroke) of said piston, which carries the rod 4" and pawl 1' With it, causing the rotation of ratchet-nut R,which being itself held against longitudinal motion draws the screw-rod S out of the air-brake cylinder and thus causes fulcrum-bl0ck H to move along the guide G away from cylinderhead a sufficient distance to compensate for the lost motion in the system, so that the next stroke of piston-head H will not exceed its normal movement.

The above-noted operation of the devices is repeated as often as the wear of the brakeshoes or slack in the system becomes sufficient to cause the travel of the piston-head of the air-brake cylinder to exceed its normal travel in applying the brakes.

It will be noted that when slack-adjuster mechanism is first applied the screw-rod S is almost entirely housed within the air-brake cylinder, where it is protected from the Weather and from dust and dirt, and that thereafter such portions thereof as must be subsequently traversed by the ratchet-nut are at all times protected, so that there is little or no danger of the accumulation of rust or dirt which might reduce the efficiency of or require greater power to operate the adjuster mechanism.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

1. The combination with an air-brake cylinder, of a cylinder-lever, a movable fulcrum therefor, a fulcrum-guide supported from the brake-cylinder head, and means for shifting the movable fulcrum, said means housed Within the air-brake cylinder; substantially as and for the purposes specified.

2. The combination with an air-brake cylinder having a perforate head provided with an inwardly-projecting tube, of a slack-ad juster having a screw-rod and nut-and-ratchet mechanism, said slack-adjuster mounted on the cylinder-head the screw-rod being housed in the tube Within the cylinder; substantially as and for the purposes specified.

3. The combination with an air-brake cylinder having a perforate cylinder-head and an inwardly-projectin g tube, of a piston-h ead having a hollow stem for the reception of the inwardly-projecting tube of the cylinderhead, a lever-fulcrum movable in a guide or stirrup mounted on the cylind er-head and provided with a screw-rod housed in the tube of the cylinder-head, a ratchet-nut arranged on the screw-rod, and means for rotating the ratchet-nut; substantially as and for the purposes specified.

In testimony whereof I affix my signature, in presence of two witnesses, this 15th day of December, 1896.

W'M. W. HOLMES.

WVitnesses:

J. CONDIT SMITH, FRANK F. KISTER. 

